class Animal(object):
    pass


# 大类
class Mammal(Animal):
    pass


class Bird(Animal):
    pass


# 各种动物
"""
class Dog(Mammal):
    pass


class Bat(Mammal):
    pass


class Parrot(Bird):
    pass


class Ostrich(Bird):
    pass

"""


class Runnable(object):
    def run(self):
        print('Running ...')


class Flyable(object):
    def fly(self):
        print('Flying...')


class Dog(Mammal, Runnable):
    pass


class Bat(Mammal, Flyable):
    pass
